Anybody who knows what the cause for the RROD knows there is no 'cure' for them. You either have to send your xbox in, trade it in (store warrenty), or open it up (voiding the warrenty) and fix it yourself. My friend put a new case on his 360, and got the rings about a year later. Since he had alreadfy modded his box, he just opened it up and fixed it.
There is no permanent 'cure' that will not void the warrenty on your box. At least, there is none known right now.